Brainstem Circuits Underlying the Prey-Catching Behavior of the Frog

Abstract

Prey-catching behavior (PCB) of the frog consists of a sequence of movements as a stimulus-response chain of the behavioral pattern in which each action presents a signal for the subsequent event. The transformation of visual information into appropriate spatiotemporal patterns of motor activity is carried out by the motor pattern generators located in the brainstem reticular formation. The motor pattern generators provide input to the motoneurons either directly or via the last-order premotor interneurons (LOPI). Although the feeding program is predetermined in this way, various sensory mechanisms control the motor activity. By using neuronal labeling methods, we have studied the morphological details of sensorimotor integration related to the hypoglossal motoneurons to provide further insight into the neuronal circuits underlying the PCB in ranid frogs. Our major findings are as follows. (1) Dendrodendritic and dendrosomatic contacts established by the crossing dendrites of hypoglossal (XII) motoneurons may serve as a morphological option for co-activation, synchronization and proper timing of the bilateral activity of tongue muscles. The crossing dendrites may also provide a feedforward amplification of various signals to the XII motoneurons. The overlapping dendritic territories of the motoneurons innervating protractor and retractor muscles may facilitate the coordinated activities of the agonistic and antagonistic muscles. (2) The musculotopic organization of the XII motoneurons is reflected in the distribution of LOPI for the protractor and retractor muscles of the tongue. (3) Direct sensory inputs from the trigeminal, vestibular, glossopharyngeal-vagal, hypoglossal and spinal afferent fibers to the XII motoneurons may modulate the basic motor pattern and contribute to the plasticity of neuronal circuits. (4) The electrical couplings observed in the vestibulocerebellar neuronal circuits may synchronize and amplify the afferent signals. The combination of chemical and electrical impulse transmission provides a mechanism by which motoneurons can be activated sequentially.

Possible neural network mediating jaw opening during prey-catching behavior of the frog

“…5 summarizes the present and previous data concerning the direct and indirect sensory input to the brainstem networks of preycatching behavior in the frog (Anderson, 2001;Antal et al, 1980;Corbacho et al, 2005;Deak et al, 2009;Harwood and Anderson, 2000;Kecskes et al, 2013Kecskes et al, , 2015Mandal and Anderson, 2010;Matesz, 1994;Matesz et al, 2008Matesz et al, , 2014Nishikawa, 2000). We can hypothesize that direct contacts of the trigeminal fibers with the trigeminal and facial motoneurons can be the morphological background of the synchronization and timing of the jaw closing and opening during the feeding movements.…”

Temporal Profile of Brain Gene Expression After Prey Catching Conditioning in an Anuran Amphibian

“…The whole brain was used from the olfactory bulbs to the caudal hindbrain, excluding the spinal cord. Therefore, the pathways responsible for control of prey catching behavior (e.g., midbrain: Ewert, 1967;medulla: Takei et al, 1987;Matesz et al, 2014) and their potential modification by learning or other processes (e.g., Carr et al, 2002) were all included in the analysis of molecular responses.…”

The Circadian Rhythm of the Behavior and Gut Microbiota in Dybowski’s Frogs (Rana dybowskii) during the Autumn Migration Period

“…However, because these studies only used basic descriptions, it is difficult to understand the essence of animal behavior at a deeper level. For this reason, many scholars have conducted in-depth research on certain behaviors of amphibians from physiological and molecular ecology perspectives [ 18 , 19 ]. For example, Woodley reviewed the relationship between chemical signals, hormones, and amphibian reproduction [ 20 ].…”